File-sharing websites generally get shut down on a pretty regular basis for a few weeks or months before popping up again under a different exact address. The Pirate Bay has been taken down probably 10 times in the last decade, yet it still exists. I imagine a different owner will take over Kickass and bring it back.
I believe Kickass Torrents can make a comeback because Piratebay, the other major torrent website on the internet, has survived numerous attempts to shut it down. The amount of people that download torrents worldwide is incredibly huge, and the fact that a lot of the media that is pirated is usually quite expensive for the average person means that pirated content is going to be shared online for a long while yet. If Kickass doesn't make its way back in its last incarnation, it will resurface under a different guise.
It is possible for kickass torrents to make a comeback, but it will be very difficult. They will need to find a differnt domain name and do a better job of hiding from law enforcement. They also need to avoid countries with strict prosecution of illegal torrenting which might mean staying out of the US.
KT was one of the largest torrent sites, but with so much publicity and so many copyright/ legal issues, I don't think it can make a comeback. The site's founder was arrested and the site is now down across all it's official domain names. With criminal investigations and Homeland Security scrutiny a comeback seems unlikely.